Nonsinging reamplifying circuits



N ONS NG NG REMWL NG- IHGU T S Illllll M. VEN TUR frequencies extending from 86,000 to 90,-

000 cycles. As it is not desired to take advantage of any frequency translation darinUn the rst transmission of the energy throng i the modulating amplifier M1, the filter A,

connecting circuits 2l and' 22, is designed M2, so that suin and difference frequencies.

result. The difference frequency corresponds to arange of frequencies extending from 70,000 cycles to 74,000 c cles corresponding to the section-line rectangle designated B in Fig. 2. The euri frequencies correspond to a range extending from 102,000 to 106,000 cycles as indicated by the lain rectangle directly above the rectangle li of Fig. 2. As the filter B interconnecting circuits 23 and 24 is designed to pass only a ran e from 70,000 to 74,000 cycles, the band mar ed B in Fig. 2 will be passed, and con sequently the energy amplified by the'devices M, and M, will again be impressed upon the input circuit of the modulating amplifier M, translated in frequency by being stepped down 16,000 cycles.

The energy transmitted through the band filter B, upon being impressed upon the modulating amplifier M beats with the locally supplied frequency of 8,000 cycles to produce a lower side band from 62,000 to 66,000 cycles and an upper side band extending rom 78,000 to 82,000 cycles. The lower band is represented by the rectangle A, in Fig. 2, and the upper band is designated by the plain rectangle immediately above the rectangle A,. The upper band suppressed by the iilter A, while the lower band is passed through said filter and irnpressed upon the modulating ainplilier M2.

The range of frequencies extending from 62,000 to 66,000 cycles impressed upon the modulating amplifier M, is stepped down in frequency by a. further step of 16,000

cycles, theV stepped down band extending from 46,000 to 50,000 cycles being assed through the filter B, to the inodu ating amplifier My Here another step down in frequency of 8,000 cycles occurs, so that a stepped doivnband extending from 36,000 to lJ2000 cycles is selected by the filter A, and impressed upon the modulating ampliierMz. The ener is now amplified and stepped down in requency to a band er.- tending from 22,000 to 26,000 cycles which band is assed through the filter B2 and, impresse upon the modulating amplifier MV The modulating amplifier M, steps this band down to a range extending from 14,000 to 18,000 cycles, the latter band being selected b the filter A, and impressed upon the modu ator Mz.

Recalling `that the band of frequencies extending from 14,000 to 18,000 cycles cor responds to a band of the same Width originally received from the transmitting station and that the original band involved two side bands and a carrier, it is apparent that the band extending from 14,000 cycles to`l8,000 cycles corresponds to an upper and lower side band associated with a carrier of 16,000 cycles. Conseqently when this band is impressed upon t 000 cycle frequency locally supplied to the modulator beats with the band to detect from the two side bands a single signal band extending irom zero to 2,000 cycles. This e modulating amplifier M2, the 16,-

signal band is selected into the circuit 25 from the circuit 23 by the filter R and actuates the receiver R.

If We examine the chart of Fig. 2, it will be seen that each of the selected lower side bands is represented by a rectangle shown in section lines, While the corresponding side band which is suppressed is represented by a plain rectangle immediately above the rectangle representing the selected band. The stepping down in frequency, it will be noted, occurs alternately in steps of 8,000 and 16,000 cycles. The advantage of stepping down by unequal steps resides in the tact that it each step should be made equal interference would occur between upper side bands which it is desired to suppress and lower side hands ot' sonic preceding step in the operation. For example, suppose We consider the band B, in Fig. 2 which has been stepped down from the band A, by a step of 16,000 cycles. lf the band B, should in turn be stepped down by beating with 16,000 cycles, the band A, would occur 8,000 cycles lower in the frequency spectrum, and t e corresponding upper side band which is to be suppressed would lie in the saine range as the band A1. As the band to be suppressed would be inverted with respect to the band .A1, this would produce inter ference.

There is a further advantage in making the successive steps unequal in the ratio of two to one, for, as lwill be observed from the diagram, this brings two of the upper side bands to be suppressed within the saine frcquency range. For example, the upper side bands corresponding to A, and B, are both in the range from 54,000 to 58,000 cycles. It the steps were so chosen that these two bands did not coincide, it would obviously be necessary to increase the distance between bands A, and B1, for example, with the result that `the stepping down of the frequcncies would have to take place by larger steps.

Consequently, the

'as might be necessary ina energy to be amplified could not be repassed through the amplifying apparatus as great av number of times given situation where the energy to be amplified is very Weak.

A modified arrangement is illustrated in Fig. 3 in which tuned circuits are used instead of band filters and in which the tubes M1 and M2 are arranged to oscillate and generate each its own stepped down frequency. For example, the tube M1 is provided with afeed-back connection 25 tuned to afrequency fo, so that the tube generates its own beating frequency. tube M2 is provided with a feed-back connection tuned to Qfo, so thatv the tube will generate a beating frequency twice that supplied to the tube M1. Each of the tubes M1 and M2 is arranged to operate not only as a modulator and an amplifier but also as an oscillator.

The operation is as follows: Assuming, for example, that a frequency band extending from 86,000 to 90,000 cycles is received by the antenna RA. and impressed upon the tube M inasmuch as the tube is oscillating at 8,000 cycles, it will produce in its output circuit bands corresponding to the sum and difference frequencies and also to the original band extending from 86,000 to 90,000 cycles. This first amplifying step is not designed to produce any frequency translation, consequently the tuned circuit will be tuned to select a band of from 86,000 to 90,000 cycles and exclude the upper an-d lower side bands. The selected band is impressed upon the tube M2 which is oscillating at 16,000 cycles. Consequently the output circuit of the tube will transmit an amplified component corresponding to the original band stepped down 16,000 cycles. This stepped down amplified component Will be selected by the tuned circuit B and impressed upon the modulator M1, which, by beating it with the self-generated frequency of 8,000 cycles will step it down 8,000 cycles further. his process is continued as in the case of Fi l until finally an amplified detected band of from zero to 2,000 cycles is selected from the output of the tube M2 .and impressed upon the receiving device R.

It will be obvious that the general principles herein disclosed may be embodied in other forms widely different from those illustrated Without departing from the spirit of the invention as defined in the following claims.

What is claimed is: I

l. An amplifying system in which the energy to be amplified is passed through the amplifier successively a number of times, comprising an amplifier, a plurality of reentrant connections from the output of said amplifier to its input, each connection being Likewise the a arranged to pass a different frequency, and means associated with said ampllfier to suply a beating frequency thereto said beating frequency being such as to produce a change in the frequency of the ener y each time it is passed through said amp nier, and each change corres onding to the frequency passed by a diff connections.

2. An amplifying system in which the energy to be amplified is passed through the amplifier successivelyv a number of times, comprising an amplifier, a plurality of reentrant connections from the output of said mplifier to its input, each connection bein arranged to pass a different frequency, an means associated' with said amplifier to supply a beating frequency thereto, said beating requency being such as to modulate the energy each time it asses therethrough to produce sum and di erence frequencies, one of the frequencies thus produced for each translation corresponding to the frequency passed by a different one of said re-entrant connections.

3'. An amplifying system in which the enerent' one of said re-entrant ergy to be amplified is passed through the amplifier successively a number of times, comprising an amplifier, a plurality of reentrant connections from the output of said amplifier to its input, each connection being arranged to pass a different frequency, means associated with said amplifier to supply a beating frequency thereto, said beating requency being such as to modulate the energy each time it asses therethrough to produce sum and dierence frequencies, one of the frequencies thus produced for each translation corresponding to the frequency passed by a different one of said4 re-entrant connections, and means associated with each reentrant connection to render it selective of a diderent onev of the successively produced difference frequencies, thereby successively stepping down the energy in the frequency spectrum as it is amplified.

4. An amplifying system in which the energy to'be amplified is passed through the amplifying apparatus successively a number of times, comprising a plurality of'amplifiers each arranged so' that its output transmits to the input of the other, the arrangements for transmitting from the output of each amplifier to the input of the succeeding amplifier each comprising a plurality of re-entrant connections, each connection being arranged to pass a different frequency, and means fassociated with each amplifier to change the frequency of the energy each time it passes through the amplifier, each change corresponding to the frequency passed by a different one of the re-entrant connections associated With its output circuit.

5. An amplifying system in which the energy to be amplified is passed through the l am 1i a 'i aratusA successivel a num-, p fying ldiJmplr'lsm' g a pl'ural1` y of ami-"g ber of times, pliers ea'ch V'arranged so that its output transmits to the input of the other, the ar,-v rangements for transmittingfrom the output of each amplifier to t input of the succeeding amplifier each comprising a plurality of re-entrant connections, each connectlon being arranged to frequency, and meansl assoclated with each amplifier to suppl a beating f uency thereto to change t e frequency of t e en-l er Ieach time it passes throu h the amer, each change correspon mg to the equency passed by a diil'erent one of the reentrant connections associated with its output circuit.

- ments for transmitting entrant connections, eac

6. An amplifying system in which the energy to be amplified is passed through the amplifying apparatus successively a number of times, comprising a plurality of amplifiers each arranged so that its output transmits to the input of the other, the arrangements for transmitting from the output of each amplifier to the input of the succeeding amplifier each comprising a plurality of reentrant connections, eac connection bein arranged to pass a different frequen an means assoclated with each ampli er to change the" uency of the energy each time it passes t rough the amplifier, each change vcorresponding to the frequency passed by a different one cf the re-entrant connections associated with its output circuit, and the chan 1n freguency produced by each amplifier ing di erent from that produced by the other.

'7. VAn amplifying system in which the energy to be amplified is y passed through the amplifying apparatus successively a number of times, comprising a plurality of ampliiers each arranged so that its outputtransmits tothe input of the other, the arrangefrom the output of each amplifier to the input of the succeeding amplifier each comprism a plurality of red E coxfirnection bein arranged to a i erent uency, an means with each amplciier to supply a beating frequency thereto to change the freqliency of the energy each time it o :fs: t rough the amplifier, each change corresponding to the frequency passed by a different one of the re-entrant connections associated with its out ut circuit, and the cha in frequency produced by each amplifiernging di erent from that produced by this oiiiir' I h h h amp' 'g steminwic teenergy to be amplifiedsis passed through the amplifier successively a number of times, comprising an amplifier, a plurality of reentrant connections from the output of said amplifier to its input, each connection being arranged to pass a different frequency, and

a different 4 thus means comprising a feed-back cou ling ascou li being'so adjusted and proportioned as noduce a beating' frequency-fertile ampli er, saidbeating requen being such as to produce achange in the equency of the energy each time it is passed through said amplifier, and each chau e corres nding to t one of'said re-entrant connections.

9. An amplifying system in which'the en` ergy to be amplified is passed through the amplifier successivel ,a number `of times, comprising an amplifier, a plurality {of reentrant connections from the output tof said amplifier to its input, each connection be' arranged to pass a different frequency, :id means comprising a feed-back' cou lin associated with said amplifier, said eedk coupling being so adjusted and proportioned as to roduce a beating frequency for the am li er, said beating frequenc being sucv as to modulate the energy eac time 1t asses therethrough to produce sum and diference frequencies, one of the frequencies produced for each translation corre spending to the frequency passed by a different one of said re-entrant connections.

10. An amplifyin system in which the enener to be ampli ed is passed through the amp ifier successively comprising an amplifier, a plurality of reentrant connections from thev output of said amplifier to its input, each connection being arranged to pass a diiferent fr uency, means comprising' a feed-back cou 11n associated with said amplifier, said Feedck coupling being so-adjusted and proportioned as to roduce a beatin frequency for the ampli er said beating requency being such as to modulate the energy each time it passes e frequency ypassed y adi erent i a number of times,

therethrough to produce sum and difference successively produced difference frequencies,

thereby successively stepping down the ener1'1 edin the frequency spectrum as it is am- P 11. An amplifin system in which the energy to be amp 'e 1s passed through the amplifying apparatus successively a number of times, comprising a plurality of amplifiers each arranged so that its output transmits to the input of the other, the arrangements for transmitting from the output of each amplifier to the input of the succeedi amplifier each comprisin" a plurality of reentrant connections, eac connection bein arranged to pass a different frequency, an means comprisin a feed-back cou ling as- Sociatcd with eac amplifier, each feed-back Lor/,451

coupling being so adjusted and proportioned as to produce a beating fre uency for the corresponding amplifier to c ange the frecllency of the energy each time it passes t rough the amplifier,` each change corresponding to the frequency passed by a differments for transmitting from the output ofv each amplifier, to the input of the succeeding amplifier each comprising a plurality of re-entrant connections, each connections beingi arranged to pass a different f ency, an means oomprlsing a feed-back oouplin associated with each am lier, each fee back coupling being so adjusted and propor- I.

tioned as to produce a beating fr uency for the corresponding amplifier to c nge the frequency of the energy each time it passes throu h the amplifier, each change correspondmg to the frequency passed by a diierent one of the re-entrant connectlonis` associated with its output circuit, and the change in frequency produced by each am lier bein d11ferent from that produc by the ot er.

In testimony whereof, `I have signed my name to this specification this 14th day of` HERMAN aman.;

May, 1923. 

